Screenshot from Un Chien Andalou, the Surrealist film that Dalí collaborated on with Luis Buñuel

Do you ever experience a crawling sensation across your skin after looking at images of cockroaches, mosquitoes, bedbugs and ticks? These jitters are common, and they tend to pass as soon as the mind moves on. But for some people, the sensation of invisible creepy-crawlers walking across their skin never goes away.

Ekbom’s syndrome, also known as delusional parasitosis, causes people to falsely believe they are infested by bugs on or under their skin. Victims may refer to the invisible invaders as ”insects, larvae, organisms, parasites, worms, and beasties” or, most commonly, bugs. Although the insects do not exist, the condition is almost always accompanied by “tactile hallucinations”—sufferers feel a crawling sensation. Sometimes they even think they see the non-existent insects.

Although this condition only received an official name in the 1930s, it has likely plagued people for much, much longer. A few years before the diagnosis became official, for example, surrealist painter Salvador Dalí reported suffering from an Ekbom’s syndrome-like incident. Popular Science recounts the story:

In 1926, a young Salvador Dalí was lying in a Paris hotel room staring at an insect crawling on the ceiling. This bothered him. Before he had fallen asleep, he had counted two, or maybe three, insects above him. If only one was left, where had the others gone?
Convinced that the crawling specks were bed bugs (or roaches or lice or ticks), Dalí frantically checked his sheets and his body to see if he’d been attacked during his nap. He found a small bump attached to his back and ran to a mirror to see if he could get a glimpse. He squeezed the bump with his fingernails to pull it off, but it wouldn’t move. He dug in, drawing blood. Still nothing.

The “bed bug” or “tick,” it turned out, was nothing more than one of Dali’s own moles. That didn’t stop him from whole-heartedly believing the mole was a parasite attacked to his skin, however, or from brutally excising it. As Dali described in his autobiography:

I made a drastic decision, and with the savagery proportionate to my frantic condition and my horror I seized a razor blade, held the tick tightly between my nails and began to cut the interstice between the tick and the skin, which offered an unbelievable resistance. But in a frenzy I cut and cut and cut, blinded by the blood which was already streaming. The tick finally yielded, and half-fainting, I fell to the floor in my own blood.

Ekbom’s syndrome can plague people for decades, and it’s possible that Dali—like many of the approximately 100,000 Americans who suffer from this syndrome today—had other episodes. Though in Dalí’s case, at least, he may have reaped creative rewards from his suffering: ants later showed up in his paintings, and in 1929, his famous film collaboration with fellow surrealist Luis Buñuel, Un Chien Andalou, ants crawl out a wound in one man’s hand.